Cabinets and enclosures are used to house and protect a wide variety of items, which may vary greatly in size and shape. A variety of cabinet configurations have been developed for the protection of items such as electrical and electronic assemblies, vacuum tubes and state-of-the-art compact high speed hybrid and digital circuits. Today, electronic assemblies differ as to the space and proportions necessary to house them. There are many cabinet and enclosure structures available in many sizes. A cabinet that measures several cubic feet may be necessary to house a high voltage system or a multi-server system, while a cabinet that measures the size of a pack of cigarettes may be sufficient to house a compact electrical or embedded electronics arrangement. However, users of such enclosures are limited to either choosing a standard size enclosure, which may be too large for their applications; or fabricating a custom size enclosure, which may require welding, a large amount of machining, and/or high tooling and other significant costs.
In many situations, it is beneficial to use a cabinet with multiple compartments. For example, in the case of an electrical circuit or circuits, it may be desirable to separate a high voltage section from a low voltage section, or a particularly noise-sensitive circuit from other circuits. In such cases, custom fabrication becomes considerably more difficult and costly. Means for construction of a cabinet or enclosure, or a set of modular interconnected cabinets or enclosures, that provide strength, ease of assembly, and appropriate size for a particular application, large or small, have yet to be realized.
A number of attempts have been made to provide a cabinet which satisfies these criteria, but typically the cost or the complexity, the size, versatility or strength have been less than desirable. By way of example, the following U.S. Patents disclose either welded or modular frame assemblies representative of cabinet structures developed in the prior art.
U.S. Pat. No. 2,167,525 to Rosendale (hereinafter Rosendale) and U.S. Pat. No. 3,265,419 to Durnbaugh, et al. (hereinafter Durnbaugh) both disclose welded cabinet structures. Rosendale employs gussets—triangular pieces of metal—welded in each corner to hold three mutually perpendicular struts in a corner arrangement. Durnbaugh eliminates such gusset members and welds the strut members directly to each other at their intersection. However, the three strut members which form each corner have different cross-sectional configurations and end profiles. Thus, the manufacture and construction of the frame is complicated. Additionally, four welds are desired to join the struts to create a rigid frame structure. The cabinet structures of Rosendale and Durnbaugh therefore, are very labor intensive.
U.S. Pat. No. 3,182,846 to La Kaff (hereinafter La Kaff) and U.S. Pat. No. 3,919,603 to Salvati (hereinafter Salvati) disclose cabinet configurations that involve mechanical assembly. In La Kaff, side frame struts are coupled to the top and base members using engaging elements formed of generally rectangular aluminum blocks, which are attached by welding to the top and bottom members and struts. The engaging elements have frustoconical portions configured to fit snugly together. The top and base members are matted via the engaging elements and bolted together. Both manufacturing cost and lack of versatility make this frame an undesirable alternative. Salvati discloses a switchgear framework including a corner tie for supporting three structural corner members together. The corner tie has three rectangular-shaped perpendicular legs with three sides and outwardly facing flanges, the three struts being slid over the leg portions. However, the struts and leg portions have different cross-sectional configurations, and the corner tie is of a generally complex configuration, such that this frame structure is not conducive to low-cost manufacturing techniques.
Finally, U.S. Pat. No. 5,066,161 to Pinney (hereinafter Pinney) discloses a simplified cabinet frame structure element. However, the simplified cabinet frame structure element of Pinney requires bends, cuts at angles on corners, and a welding process. Thus, the simplified cabinet frame structure element of Pinney is not conducive to low-cost manufacturing techniques.
In view of the foregoing, what is needed is an enclosure and cabinet system that allows for rapid, low-cost, custom fabrication of high-strength, modular enclosures. For example, an enclosure and cabinet system that require little or no welding, and little or no machining is ideal.